<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    var num = prompt('请输入三位正数：');
    var one =parseInt(num/100);
    var two = parseInt(num%100/10);
    var three =num%10;
    console.log(typeof num);
    if (num===(one*one*one)+(two*two*two)+(three*three*three)){
        console.log("是的");
    }else {
        console.log("不是的")
    }

</script>
</body>
</html>